study stuff for exams term 2 summary

Question 1

What do all physical quantities consist of

Answer 1

all physical quantities consist of a numerical magnitude and a unit

Question 2

what are the five SI base quantities and their units

Answer 2

recall the following SI base quantities and their units: mass (kg), length (m), time (s), current (A), temperature (K)

Question 3

prefixes and their symbols to indicate decimal submultiples or multiples of both base and derived units:
(Include multiplication factor)

Answer 3

pico (p) x 10 - 12
nano (n) x 10-9
micro (μ) x 10 - 6
milli (m) x 10 - 3
centi (c)x 10 -2
deci (d) x 10 - 1
kilo (k) x 10 3
mega (M) x 10 6
giga (G) x 10 9
tera (T) x 10 12

Question 4

Difference between

Answer 4

Accuracy refers to how close a measurement is to the true or accepted value. Precision refers to how close measurements of the same item are to each other.

Question 5

scalars vs vectors

Answer 5

Scalars are quantities that are fully described by a magnitude (or numerical value) alone. Vectors are quantities that are fully described by both a magnitude and a direction.

Question 6

Scalar examples

Answer 6

volume, density, speed, energy, mass, and time.

Question 7

Vector examples

Answer 7

velocity, momentum, force, and weight

Question 8

define distance

Answer 8

Distance is defined to be the magnitude or size of displacement between two positions.

Question 9

Define displacement

Answer 9

Displacement is a vector quantity that refers to how far out of place an object is

Question 10

Define speed

Answer 10

Speed is a scalar quantity that refers to “how fast an object is moving.”

Question 11

define velocity

Answer 11

Velocity is a vector quantity that refers to “the rate at which an object changes its position.”

Question 12

Define acceleration

Answer 12

Acceleration is a vector quantity that is defined as the rate at which an object changes its velocity

Question 13

describe and explain motion due to a uniform velocity in one direction and a uniform acceleration in a perpendicular direction

Answer 13

MOTION DUE TO CONSTANT VELOCITY IN ONE DIRECTION AND. A CONSTANT ACCELERATION IN A PERPENDICULAR DIRECTION. The motion of objects projected at an angle or horizontally from some height above the ground is called PROJECTILE MOTION.

Question 14

What is mass the property of

Answer 14

mass is the property of an object that resists change in motion

Question 15

f =

Answer 15

F = ma

acceleration and resultant force are always in the same direction

Question 16

What is linear momentum the product of

Answer 16

linear momentum is the product of mass and velocity

Question 17

what is force

Answer 17

force is the rate of change of momentum

Question 18

What is weight

Answer 18

weight is the effect of a gravitational field on a mass a

The weight of an object is equal to the product of its mass and the acceleration of free fall

Question 19

What increases as speed increases

Answer 19

drag force increases as speed increases

Question 20

terminal velocity

Answer 20

objects moving against a resistive force may reach a terminal (constant) velocity

Question 21

the principle of conservation of momentum

Answer 21

conservation of momentum, general law of physics according to which the quantity called momentum that characterizes motion never changes in an isolated collection of objects; that is, the total momentum of a system remains constant.

Question 22

For a perfectly elastic collision what is the relative speed of approach

Answer 22

For a perfectly elastic collision, the relative speed of approach is equal to the relative speed of separation

Question 23

will kinetic energy take place in interactions between objects

Answer 23

while momentum of a system is always conserved in interactions between objects, some change in kinetic energy may take place

Question 24

What may the weight of an object be taken as

Answer 24

understand that the weight of an object may be taken as acting at a single point known as its centre of gravity

Question 25

What is the moment of a force

Answer 25

The turning effect of a force applied to a rotational system at a distance from the axis of rotatio

Question 26

what is a couple

Answer 26

a couple is a pair of forces that acts to produce rotation only

Question 27

define and apply the torque of a couple

Answer 27

A couple is two equal forces which act in opposite directs on an object but not through the same point so they produce a turning effect. The moment (or torque) of a couple is calculated by multiplying the size of one of the force (F) by the perpendicular distance between the two forces (s).

Question 28

state the principle of moments

Answer 28

According to the principle of moments. if the algebraic sum of moments of all the forces acting on the body about the axis of rotation is zero. the body is in equilibrium. A physical balance (or beam balance) works on the principle of moments.

Question 29

When is a system in equilibrium

Answer 29

when there is no resultant force and no resultant torque, a system is in equilibrium

Question 30

Density

Answer 30

Density is the mass per unit volume. It can be measured in several ways. The most accurate way to calculate the density of any solid, liquid or gas is to divide its mass in kilograms by its volume (length × width × height) in cubic metres. The unit for density is kg/m 3.

Question 31

pressure

Answer 31

pressure, in the physical sciences, the perpendicular force per unit area, or the stress at a point within a confined fluid.

Question 32

the equation for hydrostatic pressure

Answer 32

Δp = ρgΔh

Question 33

What is the upthrust acting on an object in a fluid

Answer 33

the upthrust acting on an object in a fluid is due to a difference in hydrostatic pressure

Question 34

calculate the upthrust acting on an object in a fluid using what equation

Answer 34

the equation F = ρgV (Archimedes’ principle)

Question 35

Work done

Answer 35

work done = force × displacement in the direction of the force

Question 36

what is work

Answer 36

work, in physics, measure of energy transfer that occurs when an object is moved over a distance by an external force at least part of which is applied in the direction of the displacement

Question 37

Conservation of energy

Answer 37

The principle of energy conservation states that energy is neither created nor destroyed. It may transform from one type to another.

Question 38

the efficiency of a system is the ___

Answer 38

the efficiency of a system is the ratio of useful energy output from the system to the total energy input

Question 39

Concept of efficiency in physics

Answer 39

comparison of the energy output to the energy input in a given system. It is defined as the percentage ratio of the output energy to the input energy, given by the equation: Useful output energy/ total input energy x 100
This equation is commonly used in order to represent energy in the form of heat or power

Question 40

what is power

Answer 40

power is work done per unit time

P = W / t

Question 41

Power can also equal

Answer 41

P = Fv (Power = Force x Velocity)

Question 42

the formula for kinetic energy

Answer 42

EK = 1/2mv2

Question 43

Forumla for gravitational potential energy

Answer 43

mgΔh for gravitational potential energy